Rectifying apparatus.



Patented Apr. 25, 1916.

2 SHEETS-SHEET 2.

H. C'. SNOOK. RECTlFYiNG APPARATUS. APPLlcATlpN min DEc.4.1914.

4 ATTORNEY vpotential three phase UNITED sTATps PATENT onirica.

HOMER CLYDE SNOOK, 0F CYNW YD, PENNSYLVANIA.

RECTIPYING APPARATUS.

Orignal application filed December 26,

To all lwhom it may concern Be i-t known that I, Homin CLYDF. Snooii, a citizen of the United States, residing at Cynwyd, county of Montgomery, and State of Pennsylvania, have invente certain new and useful Improvements in Rectifying A tpparatus, of which the following is a specification.

My invention paratus for converting polyphase. current, and particularly high tension polyphase current, into uni-directional current.

My invention resides also in a high tension polyphase rectifying switch. j

This application is a division from my prior application, Serial Number 469,355, filedDecember 2G, 1908.

For an illustration of invention may take, reference is to be had to the accompanying drawings, in which:

Figure 1 is a diagrammatic view illustrating the apparatus and circuit arrangements ofvmy system.- Fig. 2 is a vertical sectional view, partly in elevation, of a high rectifying switch mounted in operative relation with a motor, inverted rotary or other suitable device, and a high potential three phase transformer. Fig. 3 is an end elevational View, partly in section, of the high potential three phase rectifying switch shown in Fig. 2. Fig. isaview graphically representing the rectified current waves and their effect in the X- ray tube.

Referring ductors of an electric supply circuit leading to the motor side M ofv a lmotor generator or inverted rotary R,.whose generator side delivers three phase alternating current to the three conductors 1, 2 and 3, a reversing or pole changing switch A. being connected in the conductors 2 and 3 for reversing the direction of energy flow in the X-ray tube X if for any reason it be in the wrong direction. In each of the conductors 1, 2 and 3 is inserted an adjustable non-inductive resistance L for maintaining the resistances of the three transformer primary circuits equal. And the three movable contacts for adjusting the resistances 4 are preferably mechanically connected together, so as to insert or remove equal amounts of resistance in each primarywy The conductors 1, 2 and 3 lead to the primaries p1, p2 and p3, of the high poto Fig. 1, L and L1 are the contential step up transformer T, each being Specification of Letters Patent.

relates to a system and apone of the forms my' Patented Apr. 25, 1916.

1908, Serial No. 469,355. Divided and this application filed December 4, 1914. Serial No. 875,410.

adjustable as to its number of turns, the three movable contacts for this purpose being preferably mechanically connected together so that the number of turns in the primaries is varied equally. These primaries are here shown connected in Y arrangement, though it is to be understood that the delta connection may be employed. The high potential secondaries s1, s2 and s3 are here shown as Y connected, as the preferred connection, though the delta connection is within `my invention. The three phase transformer T having vthese three primary and 'secondary windings is of the closed magnetic circuit type and has a minimum or practically no magnetic leakage for purposes hereinafter referred to. The neutral or common point of the three secondary windings, when Y connected, is connected by conductor 5 to earth or ground at 6. And for this reason the Y connection is preferred. From each secondary winding s1, s2 and s3 a connection is made through conductors h1, F and k3 to pairs of conducting arcs of the rectifying switch E, a choke coil D intervening in such connection if desired, for the purpose of preventing any high frequency oscillations (the coils D being high frequency choke coils) from running back to the transformer windings where they might cause insulation puncture's orbreak-downs.

From the opposed arcs of the rectifying switch E extend conductors z' and leading respectively to the cathode 7c and anode y' of the X-ray tube X. An ammeter F is connected in series with the tube X to measure the current consumed therein, such ammeter being, for example, of the typedescribed in Letters Patent of the United States No. 768,95@ heretofore granted to me.

Referring to Fig. 2, a bench or base H, of wood or other suitable material, serves -to support the high potential rectifying switch E,the transformer T (contained in the metal transformer case I, containing oil) and the motor generator or inverted rotary R. As here represented, R is an inverted rotary receiving direct current and delivering three phase alternating current. Y A wooden spindleor shaft J has metal shaft terminals m, m having bearings n, fn supported by the end walls o, 0 of the wooden covering or casing which incloses the high potential polyphase rectifying switch One of the terminal shafts m is connected any by an insulating coupling P with the shaft 1] of the inverted rotary R. Extending' through and carried by the spindle J are six metallic rods or wires 7', s, t, u, r, and lw, each incased in rubber or other insulating covering and support :12. The wooden spindle J insulates each of these six rotating cross connectors or rods from every other, and the insulating covering a', preferably of hard rubber, insulates each of the cross connectors to prevent premature or undesired sparking during operation. These six cross connectors or metallic rods are divided into three pairs, the cross connectors of each pair being disposed at right angles with each other, but the cross connectors of the second pair progress at an angle of 60 mechanical degrees with respect to the cross connectors of the tirst pair, and the cross connectors of the third pair progress at an angle 'of 60 mechanical degrees with the cross connectors of the second pair or at an angle of 60' mechanical degrees with the cross connectors of the first pair. Cooperating with the cross connectors 7', s respectively are the opposed pairs of conducting arcs 7, 8 and 9, 10, the

arcs 7 and 9 being electrically connected t0- gether and with the conductor t2 led up through the insulating tube 19 from the terminal of one of the high potential secondaries of the transformer T. Through-a similar insulating tube 20 is led up a conductor ts from the terminal of another high potential secondary which connects to the neigh boring conductingarcs 11 and 13 opposed to the conducting arcs 12 and 14, the cross connectors t and u cooperating with these opposed pairs of arcs. Similarly, through the insulating tubel 21 extends a conductor ,t1 communicating with the terminal of the third high potential secondary vwinding of the transformer T, the conductor 71.1v being connected tothe arcs 15 and 17 which are opposed to the conducting arms 16 and 18 respectively, the cross connectors c and w coperating with arcs. The cross connectors do not touch the arcs in passing them, short air gaps intervening over which the current sparks. The conducting arcs 8, 1l and 16 are electrically connected together and to the conductor z and, as seen in Fig. 1, to the anode j of the X-ray tube X. And the arcs 10, 12, and 18 are connected together and to the conductor which connects with the cathodev c of the tube X.

Between the neighboring pairs of the lower conducting arcs, as viewed in Fig. 2, which maybe styled the supply arcs, since they are Aconnected to the supply side of the switch E, are disposed the insulating barriers 22 and'23, of mica, micanite, glass, or suitable highly insulating material. And between the upper conducting arcs 8 andlO, which are on the distributing side these opposed pairs ofof the 'switch E and may, therefore, be styled distributing arcs, is disposed a similar insulating barrier 2l; and between the distributing arcs 12 and 14 is a similar insulating barrier 25; and between the distributing arcs 16 and 18 is a similar insulating barrier 26. These insulating barriers are supported, spaced and held in place by suitable means comprising vertically extending rods 27 and 28, preferably of insulating material.

The conduct-ing arcs 7 to 18 inclusive, are supported upon the tubes 29, 30, 31, 32, 33,

and 3l, of porcelain, or other insulating mathe alternating current generator.

The conducting arcs, as here shown, for a three phase system,v have an angular extent of something preferably slightly less than 60 mechanical degrees, 60 mechanical degrees in the switch E corresponding with 120 electrical degrees.

G produces two complete velectrical cycles for each revolution, this implyingl a fourpole machine. It follows, therefore, that since the cross connectors of the different pairs are 60 degrees in advance or in arrears of each other, it means that these cross con? nectors are disposed at an angle of 120 electrical degrees with respect to each other, the same being the interval in electrical degrees between the different phases of a symmetrical three phase curren The operation is asfollows: The operator brings the motor M of the inverted rotary into communication with a source of current and brings the inverted rotary or the alternating current generator thus lgenerating three .phase current of desired frequency and rotating the cross connectors of the rectifying switch E in syn chronism with that current. The transformer T then delivers high potential three phase current which and w to be rotating tion,

is rectified by the :.i eases connector w is just beginning to admit cui rent from secondary s1 through arcs 17 and 18 to the one terminal L' of the X-ray tube X. Its companion cross connector r is out of circuit as is also the cross connector u associated with the secondary lross connector t is just leaving arcs 11 and 12, having heretofore admitted current from the secondary 83 to the terminal 7c of the tube. Cross connectors is out of circuit' but its associate r is admitting current from secondary s2 through arcs 7, and S to the other terminal y' of the X-ray tube. As these cross connectors continue to rotate they keep passing both the positive waves of each phase through the tube X all in the same direction; and more than thisi they Correlate and superimpose the diii'erent half waves of the phases so that for certain periods kof time a plurality of phases coperate with each i other in impressing energy upon the tube X all in the same direction. whereby the tube is always traversed by energy, andthe minimum potential to which the tube is subjected is greater than the maximum potential delivered by any one of the secondaries alone. .The energy is all passed through the tube X in the same direction, the energy of each half wave of each phase being passed through the tube and all in the samey direction exciting the tube to great intensity, there being no time when there is no energy passing through the tube. And the minimum energy'at any instant is sutiicient to fully excite the tube. i

As seen `from Fig. l. the switch E rectifies the current in each phase, so that we have the overlapping half waves d, Z). c, a. b, and o, a, Z), and c representing the three different phases. a', and c' indicate the rectified or turned over negative (for example) half waves. And the length of the conducting arcs of the switch E being substantially 120 electrical degrees, and the angular relation of the cross `connectors with respect to the windings on the rotating member of the alternating current generator' is so chosen and fixed. that each cross connector is active or in circuit for a time corresponding with the distance d. There results then in the circuit of the tubejX a fluctuating current of frequency triple of one phase supplied by the transformer T, this triple frequency current being represented b v the curve e in the upper part of Fig. el. This curve is obtained by adding the ordinates of the curves below lduring such periods as the diderent phases are actively in circuit as controlled-by the switch E. It will be noted, therefore'.y that the minimum potential upon the terminals of the tube X. represented bv the distance f,

is greater than the potential of anv lone of the secondaries of the transformer T. This potential f is dependent uponl the maximum transtornier T, and this minimum and negative currentl the frequency of a half cycle potential of a phase multiplied by twice the sine of half theI angle between the phases. This curve shows that the tube X is constantly subjected to a potential whose minimum is f` and which is always greater than the potential delivered by one phase of the potential f is sufficient to excite the tube X to a very high intensity. This potential varies as shown by the upper curve e so that the energy through the tube X iiuctuates, but at no time has it a potential less than the potential i By having practically no inductance in the circuits of the primaries of the transformer T other than their own inductances. and by making the transformer T of a minimum or practically no magnetic leakage, and by mechanically connecting the shaft J tothe rotating element of the device generating the alternating current. ,l

secure a maximum eiliciency of conversion. along with an excitation of the tube X to an intensity which has never heretofore been attained, the features enumerated contributing to this result, and especially to the result of preventing inverse discharge in the tube X, inverse discharge being energy dou ing in the wrong direction through the tube X. i

The conducting arcs of the switch E are made somewhat less than 120 electrical degrees in extent to take care ofthe case where the currents in the three phases do not maintain an inter val of 120 electrical degrees between each other. and to take care of any other departures from the ideal conditions.

lVhile I have here illustrated my invention as involving a three phase current. it is to be understood that my invention refers to polyphase currents in-general, such as quarter phase or two phase currents or currents of other phase relations and numbers. And while l have shown the conducting arcs of the switch E in alinement. it is to be undcrstood that they may he disposed out of alinement and the cross connectors then suitably changed in their relations to the arcs.

lt is to be understood also that the arcs may-be lotherwise disposed, in which case a greater number of insulating barriers may be required. ln the arrangement illustrated a minimum of five insulating barriers is required, and this with the alinement of the conducting arcs makes the size of the rectifying switch a minimum for any given potenti al. l

Vhat I claim is:

1. A high potential polyphase rectifying switch comprising a pair of supply arcs for each phase, a pair of distributing arcs for each phase, a cross connector cooperating with each pair of supply and distributing arcs, the cross Aconnectors cooperating with the supply arcs of one phase being disposed at 180 electrical degrees with respect to cach other, a shaft for producing relative rotation between said arcs and cross connectors, the pairs of supply and distributing arcs being disposed side by side longitudinally ot said shaft, the angular relation between cross connectors for the diiieient phases and the angular extent of said arcs being such that at all times opposed supply and distributing arcs of each of a plurality of different phases are simultaneously in communication with each other, the supply arcs for all phases being disposed in alineinent with each other, and the distributing` arcs all being disposed in alinement with each other.

2. A high potential polyphase rectifying switch comprising a pair of supply arcs for each phase, a pair of distributing arcs'for each phase, a cross connector coperating with each pair of supply and distributing arcs, the cross connectors cooperating with' the supply arcs of one phase being disposed at 180 electrical degrees with respect to each other, a shaft for producing relative rotation between said arcs and cross connectors, the pairs ot supply and distributing arcs being disposed side by side longitudinally of said shaft, the angular relation between cross connectors tor the different phases and the angular extent of said arcs being such that at all times opposed supply and distributing arcs of each of a-plurality of different phases are simultaneously in communication with each other, the supply arcs for all phases being disposed in alinenient with each other, the distributing arcs all being disposed in alinement with each other, the distributing arcs opposed to one of each pair of supply arcs being connected in pai'- allel with each other. and the remainder of the distributingT arcs connected in parallel with each other.

3. A high potential polyphase rectifying switch comprising a pair 'of supply arcs connected together and to the terminal of a phase circuit. a distributing arc for each supply arc, the length of each arc in mechanical degrees being substantially half of the electrical Adegrees corresponding with the interval between phases, a cross connector for each pair of supply and distributing arcs and passing through one cycle for two electrical cycles, the cross connectors for a pair ot supply arcsv being disposed at 180 electrical degrees with respect to each other, the angular relation between cross connectors for the different phases and the angular extent of said arcs being such that at all times opposed supply and distributing arcs of each of a plurality ot different phases are sin'inltaneously in communication with each other, the distributing arcs opposed to one of each pair of supply-arcs being connected in parallel `with each'/v other. and the remaining distributing arcs connected in parallel with each other. i

A high potential polyphase rectifying switch comprising a pair of supply arcs connected together and to the terminal of a phase circuit, a distributing arc for each supply arc, the length of each arc in inecliaiiical degrees being substantially half of the electrical degrees corresponding with the interval between phases, a cross connector for each pair of supply and distributing arcs and passing through one cycle for two electrical cycles, the cross connectors for a pair of supply arcs being disposed at 180 electrical degrees with respect to each other, the angular relation between cross connectors for the different phases and the angular extent of said ai'cs being suoli that at all times opposed supply and distributing arcs of each of a plurality ot' different phases are simultaneously in communication with each other, the distributing arcs opposed to one of the arcs being connected in parallel with each other. the remaining distributing arcs connected in parallel with each other, said cross connectors and arcs being rotatable with respect to each other, said supply arcs disposed in alinement with each other and spaced longitudinally of the axis of rotation, and the distributing arcs'disposed in alinement with each other and spaced longitudinally of the axis ofi'otation.

5. A high' potential polyphase rectifying switch comprising pairs of opposed conducting arcs and cooperating cross connectors, a pair of supply arcs for each phase, a pair of distributing arcs for each phase, the supply arcs disposed in alinement with eacl". other, the distributing arcs disposed in alinement with each other, the angular relation between cross connectors for the different phases and the angular extent of said arcs being suoli that at all times opposed supply and distributing arcs of each of alpl'urality of different phases are simultaneously in communication with each other, half of the distributing arcs connected to each other and to one terminal of the consumption circuit, tlie remainder of the distributing arcs connected together and to the remaining terminal of the consumption circuit, an insulating barrier between neighboring pairs of supply arcs` and insulating barriers between distributing arcs connected to different terminals ot said consumption circuit, one of said barriers disposed between neighboring pairs of interconnected distributing arcs.

6. A high. potential three-phase rectifying switch comprising three pairs of conducting arcs in alinement with each other, opposed distributing arcs` cross connectors cooperating with the supply and distributing arcs, the angular relation between cross connectors for the different phases and the angular extent ot said arcs being such that at all times opposed supply and distributing arcs of each of a plurality ot different phases are simultaneously in communication with each other, anrinsulating barrier between the middle pair ot` supply arcs and the end pairs of supply arcs, an insulating barrier between each of the end distributing arcs and the neighboring pairs ot' intcr-cmmected arcs. and an insulating barrier between said pairs of inter-connected distributing arcs.

T. A high potential polyphase rectifying switch comprising two pairs of opposed supply and distributing arcs for each phase, the supply arcs t'or each phase being connected together. a distributing arc of each pair of distributing arcs being connected with one conductor of a consumption circuit, and the remaining distributing arcs connected with another conductor ot a consumption circuit, a relatively rotating cross connector coperating with each pair of supply and distrib uting arcs.l the cross connectors for each phase being disposed at right angles to each other, the cross connectors of the different phases being disposed at angles with respect to each other corresponding with the angle ot' phase ditierence, and the angular relation between cross connectors between the ditl'erent phases and the angular extent of said arcs being such that at all times opposed supply and distributingarcs ot' each ot' a plurality ot'. ditierent phases are simultaneously in communication with each other.

S. A high potential polyphase rectifying switch comprising two pairs of opposed supply and distributing arcs for each phase, the supply arcs Jfor each phase being connected together. a distril'iuting` arc ot cach pair o distributing arcs being connected with one conductor otl a consumption circuit, and the remaining distributing arcs connected with another conductor ot' a consumption circuit, a relatively rotating cross connector cooperating with each pair o`A supply and distributing arcs. the cross connectors for each phase being disposed at right .angles to. each other` the cross connectors of the different phases being disposed at angles with respect to each other corresponding with the angle of phase difference, the angular relation between cross connectors for the dit'ferent phases and the angular extent of said arcs being such that at alltimes opposed supply and distributing arcs of each of a plurality ot d'iterent phases are simu taneously in communication with each other, and means supporting all the supply arcs in alinement with each other and all the distributing arcs in alinement with each other.

9. The combination with a source of polyphase current. of means` 'tor tanstorming said current to high potential' polyphase current, a consumption circuit, and a polyphase rectitying switch intervening between said transforming means and said consumption circuit comprising two pairs of supply and distributing arcs t'or each phase, a uting arc ot each phase connected to one conductor ot' said consumption circuit, the remaining distributing arcs connected to the other conductor ot said consumption circuit means connecting together the supply arcs ot each phase, and cross connectors rotating with respect to said arcs and separated therefrom by air gaps, the angular relation between cross connectors for the dii-'ferent phases and the angular extent of said arcs being such that at all times opposed supply and distributing arcs or' each of a plurality of different phases are sin'iultaneously in communication with each other, whereby nninterrupted current is delivered to said consumption circuit.

10. high potential three-phase rectifying switch comprising a pair ot' supply arcs for each phase, a pair ol" distributing arcs for each phase, a cross connector coperating with each pair of supply and distributing arcs, the cross connectors cooperating with the supply arcs ot one phase being disposed at 180 electrical degrees with respect to each other, means for producing relative rotation between said arcs and cross connectors, the angular extent of said arcs being substantially 120 electrical degrees, the angular length ot said arcs and the angular relation ot` the cross connectors for the ditterent phases being such that at all times opposed supply and distributing arcs ot each ot' a plurality ot' different phases are simultaneously in communication with each other.

11. A high potential polyphase rectitying switch comprising a switching mechanism for each phase comprising stationary and movable conductors cooperating with that phase only to direct current always in the same direction through the consumption cir cuit. the movable elements ot' all said mechanisms moring in unison with each other and in synchronism with the current, at least two ot said switching mechanisms being at all times and simultaneously in communication with the consumption circuit.

12. A high potential polyphase rectitying switch comprising a switching mechanism distribfor each phase comprising stationary and` eaeh phane comprising i'elativel)Y movable Switehel of Said two switehe' beingy Simularesv aml ei'oss connectors cooperating taneonsli' ont o'll eommnnieation with the through .spark gaps lo ilil'eet cin-rent always eonsnmption eiienit.

in the l ame (lii'eetion to tlnl Consumption cilln testimoniY whereof l have hereunto atenil. the movallle elements` oi all said fixed my signature in the pi'esenee of the 15 switehl movingr in unison with each other two subscribing witnesses. aml in syneln'onism with the ein-Vent. at HOMER CLYDE SOOK. least two of said switches ot (lill'eient paiiS lYitnesses: being' at all times in communication with Ameli S. )basin l@ he consumption circuit, the Companion E. A. LYONS. 

